1. Field of the Invention
The present invention relates to a development apparatus and a development method which develop a resist coating film subjected pattern exposure.
2. Description of the Related Art
In a photolithography process for a semiconductor device, a system in which a coating/development apparatus is combined with an exposure device is used. A development nozzle of the coating/development apparatus is provided with a linear discharge opening which is equal to or longer than a diameter of a semiconductor wafer W in order to improve uniformity of processing. The development nozzle is arranged in such a manner that this linear discharge opening is placed in close proximity to a resist coating film on the wafer W, a developer is discharged toward the wafer W which is in a static state, and the development nozzle is moved for scanning from one end side toward the other end side of the wafer W. As a result, a liquid film of the developer having a thickness of, e.g., approximately 3 mm is formed on the resist coating film. When a state in which the liquid film of this developer is mounted is maintained for a predetermined time, the resist coating film is developed (static development), and a predetermined circuit pattern is formed. Then, the wafer W is cleaned with a rinse agent and dried.
Meanwhile, in a period that the developer is present on the wafer W, the developer already existing on the wafer and the new developer which has been just discharged from the nozzle are coupled with each other by a function of the surface tension. At this time, since the nozzle is in a moving state whilst the wafer W is in the static state, a liquid flow (of small flow rate) may be produced in the liquid film of the developer on the wafer W due to a swing-back movement (a function of an inertial force) of the developer in some cases. When this liquid flow is generated in the developer on the wafer W, slight unevenness is generated in a developer concentration (a concentration of a resist dissolving component) in a wafer plane. As a result, since progress of a development reaction becomes non-homogeneous in the wafer plane and unevenness is produced in a resist resolution, there is a risk of a reduction in uniformity of a pattern line width which is finally formed in the wafer plane.
As one technique which suppresses such a liquid flow in a liquid film of a developer, there has been proposed Jpn. Pat. Appln. KOKAI Publication No. 2003-100589 (see paragraphs 0015 to 0018, FIG. 4). In this conventional technique, a plate 12 having a plurality of holes 11 formed therein is arranged to face a wafer W, and a developer is supplied onto the wafer W through these holes 11. According to this technique, since a swing-back movement of the developer occurs on the plate 12 which is in a static state, a liquid flow of the developer is not generated on the wafer W.
However, this conventional technique has the following problems.
The plurality of holes 11 may include holes 11 through which the developer is not transmitted due to a function of the surface tension in some cases. Therefore, as seen from a plane of the plate 12, there are formed a distribution of holes 11 through which the developer is transmitted and the holes 11 through which the developer is not transmitted, whereby a liquid film of the developer having a uniform thickness cannot be formed on the wafer W plane in some cases. Unevenness in line width accuracies caused due to such non-uniformity of the thickness of the developer has not been regarded as a problem in particular. In recent years, however, with further advancement of miniaturization of a device circuit, demand from users for forming a detailed pattern with a thinner line width has increased.